ange-ftp-add-file-entry-alist is a variable defined in `ange-ftp.el'.
Its value is
((vms . ange-ftp-vms-add-file-entry))

Alist saying how to add file entries on certain OS types.
Association list of pairs (TYPE . FUNC), where FUNC is a function
to be used to add a file entry for the OS TYPE.
The main reason for this alist is to deal with file versions in VMS.